How to get CPU speed on Linux

CPU clock speed is the number of cycles your CPU executes every second. The speed was just a single number measured in MHz and then GHz. Nowadays, CPUs can boost their clock speed, and with multi-core CPUs or processors, things get even more complicated. In essence, when trying to figure out the speed of a CPU, you might want to know its minimum (base), maximum (boost), and current speed. You'll also want to see this speed for all the CPU cores.

Clock speed is not an absolute measure of the CPU's performance. This is because there are countless optimizations in modern CPUs that higher clock speed does not always ensure better performance in real-life usage.

There are several tools in Linux that you can use to show the speed of your CPU. Some are installed by default in most Linux systems, while others require manual installation. Each tool also provides varying details you may or may not find sufficient.

1. Lauch terminal.
2. Get CPU model to view official speed from manufacturer's product specification.

   $ lscpu | grep ^Model\ name
   Model name:                      Intel(R) Core(TM) i7-10510U CPU @ 1.80GHz

   Related: How to show CPU information in Linux

3. Get maximum speed for the CPU.

   $ sudo  dmidecode -t processor | grep "Max Speed"
     Max Speed: 4900 MHz

4. Get current speed of the CPU.

   $ sudo  dmidecode -t processor | grep "Current Speed"
     Current Speed: 1683 MHz

5. Install auto-cpufreq for your system.

   $ sudo snap install auto-cpufreq #Ubuntu

6. Run auto-cpufreq to view live frequency or speed for all CPU cores.

   $ sudo auto-cpufreq --monitor
   ##### snipped
   ------------------------------ Current CPU stats ------------------------------
   
   CPU max frequency: 4900 MHz
   CPU min frequency: 400 MHz
   
   Core  Usage Temperature Frequency
   CPU0:   0.0%     44 °C      900 MHz
   CPU1:   3.0%     43 °C     2300 MHz
   CPU2:   5.9%     43 °C     2477 MHz
   CPU3:   1.0%     42 °C     2300 MHz
   CPU4:   0.0%     44 °C     2300 MHz
   CPU5:   2.0%     43 °C      902 MHz
   CPU6:   1.0%     43 °C     2300 MHz
   CPU7:   0.0%     42 °C      900 MHz
   ##### snipped